Trailer-based energy capture and management

ABSTRACT

A through the road (TTR) hybridization strategy is proposed to facilitate introduction of hybrid electric vehicle technology in a significant portion of current and expected trucking fleets. In some cases, the technologies can be retrofitted onto an existing vehicle (e.g., a trailer, a tractor-trailer configuration, etc.). In some cases, the technologies can be built into new vehicles. In some cases, one vehicle may be built or retrofitted to operate in tandem with another and provide the hybridization benefits contemplated herein. By supplementing motive forces delivered through a primary drivetrain and fuel-fed engine with supplemental torque delivered at one or more electrically-powered drive axles, improvements in overall fuel efficiency and performance may be delivered, typically without significant redesign of existing components and systems that have been proven in the trucking industry.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No. 16/828,797, filed Mar. 24, 2020, now U.S. Pat. No. 10,744,888, issued on Aug. 18, 2020, which is a continuation of U.S. patent application Ser. No. 16/371,597 filed Apr. 1, 2019, now U.S. Pat. No. 10,596,913, issued Mar. 24, 2020, which is a continuation of U.S. patent application Ser. No. 15/721,371, filed Sep. 29, 2017, now U.S. Pat. No. 10,245,972, issued Apr. 2, 2019, which is a continuation-in-part of U.S. patent application Ser. No. 15/618,737, filed on Jun. 9, 2017, now U.S. Pat. No. 9,802,508, issued Oct. 31, 2017, which is a continuation of U.S. patent application Ser. No. 15/144,769, filed on May 2, 2016, now U.S. Pat. No. 9,694,712, issued Jul. 4, 2017, which claims priority to U.S. Provisional Patent Application No. 62/179,209, filed on May 1, 2015. U.S. patent application Ser. No. 15/721,371, filed Sep. 29, 2017, now U.S. Pat. No. 10,245,972, issued Apr. 2, 2019, further claims priority to U.S. Provisional Patent Application No. 62/460,734, filed on Feb. 17, 2017 and U.S. Provisional Patent Application No. 62/403,000, filed on Sep. 30, 2016, the entire disclosures of which are herein incorporated by reference.

BACKGROUND Field of the Invention

The invention relates generally to hybrid vehicle technology, and in particular to systems and methods to intelligently control regeneration and reuse of captured energy in a through-the-road (TTR) hybrid configuration.

Description of the Related Art

The U.S. trucking industry consumes about 51 billion gallons of fuel per year, accounting for over 30% of overall industry operating costs. In addition, the trucking industry spends over $100 billion on fuel annually, and the average fuel economy of a tractor-trailer (e.g., an 18-wheeler) is only about 6.5 miles per gallon. For trucking fleets faced with large fuel costs, techniques for reducing those costs would be worth considering.

Hybrid technology has been in development for use in the trucking industry for some time, and some hybrid trucks have entered the market. However, existing systems are generally focused on hybridizing the drivetrain of a heavy truck or tractor unit, while any attached trailer or dead axles remain a passive load. Thus, the extent to which the fuel efficiency of a trucking fleet may be improved using these technologies may be limited to the fuel efficiencies obtained from improvement of the hybrid drivetrain and the in-fleet adoption of such hybrid drivetrain technologies. Given the large numbers of heavy trucks and tractor units already in service and their useful service lifetimes (often 10-20 years), the improved hybrid drivetrains that are candidates for introduction in new vehicles would only address a small fraction of existing fleets. Improved techniques, increased adoption, and new functional capabilities are all desired.

SUMMARY

It has been discovered that a through-the-road (TTR) hybridization strategy can facilitate introduction of hybrid electric vehicle technology in a significant portion of current and expected trucking fleets. In some cases, the technologies can be retrofitted onto an existing vehicle (e.g., a truck, a tractor unit, a trailer, a tractor-trailer configuration, at a tandem, etc.). In some cases, the technologies can be built into new vehicles. In some cases, one vehicle may be built or retrofitted to operate in tandem with another and provide the hybridization benefits contemplated herein. By supplementing motive forces delivered through a primary drivetrain and fuel-fed engine with supplemental torque delivered at one or more electrically-powered drive axles, improvements in overall fuel efficiency and performance may be delivered, typically without significant redesign of existing components and systems that have been proven in the trucking industry.

In general, through-the-road (TTR) designs using control strategies such as an equivalent consumption minimization strategy (ECMS) or adaptive ECMS are contemplated and implemented at the supplemental torque delivering electrically-powered drive axle (or axles) in a manner that follows operational parameters or computationally estimates states of the primary drivetrain and/or fuel-fed engine, but does not itself participate in control of the fuel-fed engine or primary drivetrain. Instead, techniques of the present invention rely on operating parameters that can be observed and/or kinematic variables that are sensed to inform its controller.

In some embodiments, an ECMS-type controller for the electrically-powered drive axle is not directly responsive to driver-, autopilot- or cruise-type throttle controls of the fuel-fed engine or gear selections by a driver or autopilot in the primary drivetrain. Instead, the controller is responsive to sensed pressure in a brake line for regenerative braking, to computationally-estimated operational states of the fuel-fed engine or of the drive train, and to other sensed parameters. In some cases, observables employed by the controller include information retrievable via a CANbus or SAE J1939 vehicle bus interface such as commonly employed in heavy-duty trucks. While the ECMS-type controller employed for the electrically-powered drive axle (or axles) adapts to the particular characteristics and current operation of the fuel-fed engine and primary drivetrain (e.g., apparent throttle and gearing), it does not itself control the fuel-fed engine or of the primary drivetrain.

In some embodiments of the present invention, an apparatus includes: a towed vehicle for use in combination with a towing vehicle, the towed vehicle having an electrically powered drive axle configured to supply supplemental torque to one or more wheels of the towed vehicle and to thereby supplement, while the towed vehicle travels over a roadway and in at least some modes of operation, primary motive forces applied through a separate drivetrain of the towing vehicle; an energy store on the towed vehicle, the energy store configured to supply the electrically powered drive axle with electrical power and further configured to receive energy recovered using the drive axle in a regenerative braking mode of operation; and an electrical power interface to supply electrical power from the energy store to the towing vehicle.

In some embodiments, the apparatus further includes the towing vehicle; and a heating, ventilation or cooling system on the towing vehicle, the heating, ventilation or cooling system coupled to receive electrical power from the energy store on the towed vehicle via the electrical power interface.

In some embodiments, the energy store on the towed vehicle includes a battery or battery array.

In some embodiments, the apparatus further includes an inverter coupled between the battery or battery array and the electrical power interface to supply AC power to the towing vehicle.

In some embodiments, the apparatus further includes a step-down DC-DC power supply coupled between the battery or battery array and the electrical power interface to supply DC power to the towing vehicle.

In some embodiments, the apparatus further includes an electrical cable for transferring electrical power from the energy store on the towed vehicle to towing vehicle and for bidirectionally conveying data between the towing vehicle and at least a battery management system of the towed vehicle.

In some embodiments, the apparatus further includes a control interface in the towing vehicle, the control interface coupled to the battery management system of the towed vehicle via the electrical cable, the control interface providing one of more of: in-towing-vehicle display of state of charge for the energy store on the towed vehicle; a switch or control of a switch to enable and disable supply of electrical power to the towing vehicle; and mode control for selectively controlling an operating mode of the battery management system, wherein in at least one selectable mode, energy recovered using the drive axle in a regenerative braking mode is used to bring the energy store to a substantially full state of charge, and wherein in at least another selectable mode, state of charge is managed to a dynamically varying level based at least in part on uphill and downhill grades along current or predicted route of travel.

In some embodiments, the control interface is integrated with a heating, ventilation or cooling system on the towing vehicle, the heating, ventilation or cooling system powered from the energy store on the towed vehicle at least during some extended periods of time during which an engine of the towing vehicle is off.

In some embodiments of the present invention, a method includes: supplying supplemental torque to one or more wheels of a towed vehicle using an electrically powered drive axle on the towed vehicle to supplement, while the towed vehicle travels over a roadway and in at least some modes of operation, primary motive forces applied through a separate drivetrain of a towing vehicle; supplying the electrically powered drive axle with electrical power from an energy store on the towed vehicle, the energy store configured to receive and store energy recovered using the drive axle in a regenerative braking mode of operation; and supplying electrical power to the towing vehicle from the energy store on the towed vehicle.

In some embodiments, the method further includes supplying electrical power from the energy store on the towed vehicle to a heating, ventilation or cooling system on the towing vehicle.

In some embodiments, the energy store on the towed vehicle includes a battery or battery array.

In some embodiments, the method further includes using an inverter coupled between the battery or battery array and the electrical power interface to supply AC power to the towing vehicle.

In some embodiments, the method further includes using a step-down DC-DC power supply coupled between the battery or battery array and the electrical power interface to supply DC power to the towing vehicle.

In some embodiments, the method further includes transferring electrical power from the energy store on the towed vehicle to towing vehicle via an electrical cable; and bidirectionally conveying data between the towing vehicle and at least a battery management system of the towed vehicle via the electrical cable.

In some embodiments, the method further includes providing a control interface in the towing vehicle, the control interface coupled to the battery management system of the towed vehicle via the electrical cable, the control interface including one of more of: in-towing-vehicle display of state of charge for the energy store on the towed vehicle; a switch or control of a switch to enable and disable supply of electrical power to the towing vehicle; and mode control for selectively controlling an operating mode of the battery management system, wherein in at least one selectable mode, energy recovered using the drive axle in a regenerative braking mode is used to bring the energy store to a substantially full state of charge, and wherein in at least another selectable mode, state of charge is managed to a dynamically varying level based at least in part on uphill and downhill grades along current or predicted route of travel.

In some embodiments, the control interface is integrated with the heating, ventilation or cooling system on the towing vehicle, the heating, ventilation or cooling system powered from the energy store on the towed vehicle at least during some extended periods of time during which an engine of the towing-vehicle is off.

In some embodiments, the method further includes selectively controlling an operating mode of a battery management system, wherein in at least one selectable mode, energy recovered using the drive axle in a regenerative braking mode is used to bring the energy store to a substantially full state of charge, and wherein in at least another selectable mode, state of charge is managed to a dynamically varying level based at least in part on uphill and downhill grades along current or predicted route of travel.

In some embodiments, the selective control is provided from a control interface of a heating, ventilation or cooling system on the towing vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is illustrated by way of example and not limitation with reference to the accompanying figures, in which like references generally indicate similar elements or features.

FIG. 1A depicts a bottom view of a hybrid suspension system, in accordance with some embodiments;

FIG. 1B depicts a top view of the hybrid suspension system, in accordance with some embodiments;

FIG. 1C depicts an exemplary tractor-trailer vehicle, including the hybrid suspension system, in accordance with some embodiments;

FIGS. 2A-2F illustrate a control system circuit, which may be housed within (or otherwise integrated with) the hybrid suspension system of FIGS. 1A and 1B, in accordance with some embodiments;

FIG. 3 depicts an exemplary controller area network (CAN bus) that may be used for communication of the various components of the control system circuit of FIGS. 2A-2F, in accordance with some embodiments;

FIG. 4 is a functional block diagram of a hardware and/or software control system, in accordance with some embodiments;

FIG. 5A is a flow diagram that illustrates a control strategy employed in certain equivalent consumption minimization strategy (ECMS) or adaptive ECMS-type controller designs that may be employed in a hybrid suspension system and/or a TTR hybrid system, in accordance with some embodiments;

FIG. 5B is a flow diagram that illustrates a method for controlling a hybrid suspension system, in accordance with some embodiments;

FIG. 5C is a flow diagram that illustrates an additional aspect of a method such as illustrated in FIG. 5B for controlling the hybrid suspension system, in accordance with some embodiments;

FIG. 6 is an exemplary functional block diagram illustrating control of an on-trailer hybrid suspension system, in accordance with some embodiments; and

FIG. 7 illustrates an embodiment of an exemplary computer system suitable for implementing various aspects of the control system and methods of FIGS. 5A-5C, in accordance with some embodiments.

Skilled artisans will appreciate that elements or features in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions or prominence of some of the illustrated elements or features may be exaggerated relative to other elements or features in an effort to help to improve understanding of certain embodiments of the present invention(s).

DESCRIPTION

The present application describes a variety of embodiments, or examples, for implementing different features of the provided subject matter. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.

In particular, the present disclosure describes designs and techniques for providing an energy management system and related methods in the context of systems and components typical in the heavy trucking industry. Some embodiments of the present invention(s) provide a hybridized suspension assembly (e.g., an electrically driven axle, power source, controller, etc. that may be integrated with suspension components) affixed (or suitable for affixing) underneath a vehicle (e.g., a truck, tractor unit, trailer, tractor-trailer or tandem configuration, etc.) as a replacement to a passive suspension assembly. In various non-limiting example configurations, a hybridized suspension assembly can be part of a trailer that may be towed by a powered vehicle, such as a fuel-consuming tractor unit.

As described in more detail below, a hybridized suspension assembly is but one realization in which an electrically driven axle operates largely independently of the fuel-fed engine and primary drivetrain of a powered vehicle and is configured to operate in a power assist, regeneration, and passive modes to supplement motive/braking forces and torques applied by the primary drivetrain and/or in braking. In general, one or more electrically driven axles may supplement motive/braking forces and torques under control of a controller (or controllers) that does not itself (or do not themselves) control the fuel-fed engine and primary drivetrain. Instead, a control strategy implemented by an electric drive controller seeks to follow and supplement the motive inputs of the fuel-fed engine and primary drivetrain using operating parameters that are observable (e.g., via CANbus or SAE J1939 type interfaces), kinematics that are sensed and/or states that may be computationally estimated based on either or both of the foregoing. In some embodiments, based on such observed, sensed or estimated parameters or states, the electric drive controller applies an equivalent consumption minimization strategy (ECMS) or adaptive ECMS type control strategy to modulate the motive force or torque provided, at the electrically driven axle(s), as a supplement to that independently applied using the fuel-fed engine and primary drivetrain of the powered vehicle.

By supplementing the fuel-fed engine and primary drivetrain of the powered vehicle, some embodiments of the present invention(s) seek to simultaneously optimize fuel consumption of the powered vehicle, energy consumption of the hybrid suspension assembly, and/or state of charge (SOC) of on-board batteries or other energy stores. In some cases, such as during stopovers, embodiments of the present disclosure allow the fuel-fed engine to shut down rather than idle. In some cases, energy consumption management strategies may take into account a desired SOC at scheduled, mandated or predicted stopovers. Among other advantages, embodiments disclosed herein provide for a significant reduction in fuel consumption (e.g., an average of about 30%), a built-in auxiliary power unit (APU), enhanced stability control, improved trailer dynamics, and a host of other benefits, at least some of which are described in more detail below.

Referring now to FIGS. 1A-1C, illustrated therein is a hybrid suspension system 100. As used herein, the term hybrid suspension system is meant to convey to a person of skill in the art having benefit of the present disclosure, a range of embodiments in which some or all components of a supplemental electrically driven axle, often (though not necessarily) including a controller, a power source, brake line sensors, CANbus or SAE J1939 type interfaces, sensor packages, off-vehicle radio frequency (RF) communications and/or geopositioning interfaces, etc. are packaged or integratable with components that mechanically interface one or more axles and wheels to the frame or structure of a vehicle and which typically operate (or interface with additional components) to absorb or dampen mechanical perturbuations and maintain tire contact with a roadway during travel thereover. In some though not all embodiments, a hybrid suspension system can take on the form or character of an assembly commonly referred to in the U.S. trucking industry as a slider box. In some though not all embodiments, a hybrid suspension system may be or become more integral with a vehicle frame and need not have the modular or fore/aft adjustability commonly associated with slider boxes.

Likewise, the “hybrid” or hybridizing character of a hybrid suspension system, such as hybrid suspension system 100, will be understood by persons of skill in the art having benefit of the present disclosure in the context of its role in hybridizing the sources of motive force or torque available in an over-the-road vehicle configuration that includes it. Accordingly, a hybrid suspension system including an electrically-driven axle and controller for coordinating its supplementation of motive force or torques need not, and typically does not itself include, the additional drive axles driven by the fuel fed engine to which it contributes a hybrid or hybridizing source of motive force or torque. Thus, the tractor-trailer configuration (160) illustrated in FIG. 1C is exemplary and will be understood to include a hybrid suspension system, notwithstanding the ability of the trailer (170) to be decoupled from tractor units (e.g., tractor unit 165) that provide the fuel fed engine and primary drivetrain to which it acts as a supplement. Correspondingly, a vehicle such as a heavy truck having a single frame or operable as or with tandem trailers (not specifically shown in FIG. 1C) will be understood to be amenable to inclusion of one or more hybrid suspension systems.

In view of the foregoing, and without limitation, hybrid suspension system-type embodiments are now described with respect to specific examples.

Hybrid Suspension System

As described in more detail below, the hybrid suspension system 100 may include a frame 110, a suspension, one or more drive axles (e.g., such as a drive axle 120), at least one electric motor-generator (e.g., such as an electric-motor generator 130) coupled to the at least one or more drive axles, an energy storage system (e.g., such as a battery array 140), and a controller (e.g., such as a control system 150). In accordance with at least some embodiments, the hybrid suspension system 100 is configured for attachment beneath a trailer. As used herein, the term “trailer” is used to refer to an unpowered vehicle towed by a powered vehicle. In some cases, the trailer may include a semi-trailer coupled to and towed by a truck or tractor (e.g., a powered towing vehicle). By way of example, FIG. 1C illustrates a tractor-trailer vehicle 160 that includes a tractor 165 coupled to and operable to tow a trailer 170. In particular, and in accordance with embodiments of the present disclosure, the hybrid suspension system 100 is coupled underneath the trailer 170, as a replacement to a passive suspension assembly, as discussed in more detail below. For purposes of this discussion, the tractor 165 may be referred to generally as a “powered towing vehicle” or simply as a “powered vehicle”.

To be sure, embodiments of the present disclosure may equally be applied to other types of trailers (e.g., utility trailer, boat trailer, travel trailer, livestock trailer, bicycle trailer, motorcycle trailer, a gooseneck trailer, flat trailer, tank trailer, farm trailer, or other type of unpowered trailer) towed by other types of powered towing vehicles (e.g., pickup trucks, automobiles, motorcycles, bicycles, buses, or other type of powered vehicle), without departing from the scope of this disclosure. Likewise, although components are introduced and described in the context of an exemplary suspension assembly for a trailer, persons of skill in the art having benefit of the present disclosure will appreciate adaptations of configurations and components introduced in the exemplary trailer context to supplemental electrically driven axle applications such as affixed (or suitable for affixing) underneath a vehicle (e.g., a truck, tractor unit, trailer, tractor-trailer or tandem configuration, etc.).

Vehicles may utilize a variety of technologies and fuel types such as diesel, gasoline, propane, biodiesel, ethanol (E85), compressed natural gas (CNG), hydrogen internal combustion engine (ICE), homogeneous charge compression ignition (HCCI) engine, hydrogen fuel cell, hybrid electric, plug-in hybrid, battery electric, and/or other type of fuel/technology. Regardless of the type of technology and/or fuel type, the powered towing vehicle (or more generally the fuel-fed engine of a powered vehicle) may have a particular fuel efficiency. As described below, and among other advantages, embodiments of the present disclosure provide for improved fuel efficiency of the powered vehicle, as described in more detail herein. More generally, and in accordance with various embodiments, the hybrid suspension system 100 described herein is configured (or may be adapted) for use with any type of trailer or powered vehicle.

In addition, the hybrid suspension system 100 is configured to operate largely independently of the fuel-fed engine and primary drivetrain of a powered vehicle and, in some cases, autonomously from the engine and drivetrain controls of the powered vehicle. As used herein, “autonomous” operation of the hybrid suspension system 100 is terminology used to describe an ability of the hybrid suspension system 100 to operate without commands or signals from the powered towing vehicle, to independently gain information about itself and the environment, and to make decisions and/or perform various functions based on one or more algorithms stored in the controller, as described in more detail below. “Autonomous” operation does not preclude observation or estimation of certain parameters or states of a powered vehicle's fuel-fed engine or primary drivetrain; however, in some embodiments of the present invention(s), electrically driven axles are not directly controlled by an engine control module (ECM) of the powered vehicle and, even where ECMS or adaptive ECMS-type control strategies are employed, no single controller manages control inputs to both the supplemental electrically driven axle(s) and the primary fuel-fed engine and drivetrain.

A trailer, as typically an unpowered vehicle, includes one or more passive axles. By way of example, embodiments of the present disclosure provide for replacement of the one or more passive trailer axles with one or more powered axles. For example, in at least some embodiments, the hybrid suspension system 100 may replace a passive tandem axle with a powered tandem axle, as shown in the example of FIG. 1C. In accordance with some embodiments the present invention(s), the hybrid suspension system 100 can be configured to provide, in a first mode of operation, a motive rotational force (e.g., by an electric motor-generator coupled to a drive axle) to propel the hybrid suspension system 100, and thus the trailer under which is attached, thereby providing an assistive motive force to the powered towing vehicle. Thus, in some examples, the first mode of operation may be referred to as a “power assist mode.” Additionally, in some embodiments, the hybrid suspension system 100 is configured to provide, in a second mode of operation, a regenerative braking force (e.g., by the electric motor-generator coupled to the drive axle) that charges an energy storage system (e.g., the battery array). Thus, in some examples, the second mode of operation may be referred to as a “regeneration mode.” In some examples, the hybrid suspension system 100 is further configured to provide, in a third mode of operation, neither motive rotational nor regenerative braking force such that the trailer and the attached hybrid suspension system 100 are solely propelled by the powered towing vehicle to which the trailer is coupled. Thus, in some examples, the third mode of operation may be referred to as a “passive mode.”

In providing powered axle(s) to the trailer (e.g., by the hybrid suspension system 100), embodiments of the present disclosure result in a significant reduction in both fuel consumption and any associated vehicle emissions, and thus a concurrent improvement in fuel efficiency, of the powered towing vehicle. In addition, various embodiments may provide for improved vehicle acceleration, vehicle stability, and energy recapture (e.g., via regenerative braking) that may be used for a variety of different purposes. For example, embodiments disclosed herein may use the recaptured energy to apply the motive rotational force using the electric motor-generator and/or provide on-trailer power that may be used for powering a lift gate, a refrigeration unit, a heating ventilation and air conditioning (HVAC) system, pumps, lighting, communications systems, and/or providing an auxiliary power unit (APU), among others. It is noted that the above advantages and applications are merely exemplary, and additional advantages and applications will become apparent to those skilled in the art upon review of this disclosure.

Referring again to FIG. 1A, illustrated therein is a bottom view of an exemplary hybrid suspension system 100 which shows the frame 110, the drive axle 120, a passive axle 125, and wheels/tires 135 coupled to ends of each of the drive axle 120 and the passive axle 125. In some embodiments, the electric motor-generator 130 is coupled to the drive axle 120 by way of a differential 115, thereby allowing the electric motor generator 130 to provide the motive rotational force in the first mode of operation, and to charge the energy storage system (e.g., the battery array) by regenerative braking in the second mode of operation. Note that in some embodiments, components such as the electric motor generator, gearing and any differential may be more or less integrally defined, e.g., within a single assembly or as a collection of mechanically coupled components, to provide an electrically-driven axle. While shown as having one drive axle and one passive axle, in some embodiments, the hybrid suspension system 100 may have any number of axles, two or more drive axles, as well as multiple electric-motor generators on each drive axle. In addition, axles of the hybrid suspension system (e.g., the drive axle 120 and the passive axle 125) may be coupled to the frame 110 by a leaf spring suspension, an air suspension, a fixed suspension, a sliding suspension, or other appropriate suspension. In some embodiments, the wheels/tires 135 coupled to ends of one or both of the drive axle 120 and the passive axle 125 may be further coupled to a steering system (e.g., such as a manual or power steering system), thereby providing for steering of the hybrid suspension system 100 in a desired direction.

With reference to FIG. 1B, illustrated therein is a top view of the hybrid suspension system 100 showing the battery array 140 and the control system 150. In various embodiments, the battery array 140 and the control system 150 may be coupled to each other by an electrical coupling 145. In addition, the electric motor-generator 130 may be coupled to the control system 150 and to the battery array 140, thereby providing for energy transfer between the battery array 140 and the electric motor-generator 130. In various examples, the battery array 140 may include one or more of an energy dense battery and a power dense battery. For example, in some embodiments, the battery array 140 may include one or more of a nickel metal hydride (NiMH) battery, a lithium ion (Li-ion) battery, a lithium titanium oxide (LTO) battery, a nickel manganese cobalt (NMC) battery, a supercapacitor, a lead-acid battery, or other type of energy dense and/or power dense battery.

Control System Architecture and Components

As discussed above, the hybrid suspension system 100 is configured to operate autonomously and in at least three modes of operation: (i) a power assist mode, (ii) a regeneration mode, and (iii) a passive mode. In particular, and in various embodiments, the hybrid suspension system 100 is operated in one of these three modes by way of the control system 150 (e.g., in conjunction with suitable program code, as discussed below). Various aspects of the control system 150, including system architecture and exemplary components, are described in more detail below with reference to FIGS. 2A-2F, 3, and 4 .

Referring first to FIGS. 2A-2F, illustrated therein is a control system circuit 200 that may be housed within the control system 150. It is noted that the control system circuit 200, and the components shown and described herein are merely exemplary, and other components and/or circuit architecture may be used without departing from the scope of the this disclosure. FIG. 2A shows an AC motor controller 202, which may be used to actuate the electric motor-generator 130. By way of example, and in some cases, the AC motor controller 202 may include a Gen4 Size 8 controller manufactured by Sevcon USA, Inc. of Southborough, Mass. In some embodiments, the AC motor controller 202 is coupled to an AC motor controller relay 238 (FIG. 2D). As described below with reference to FIG. 3 , the AC motor controller 202 may communicate with other components of the control system circuit 200 by way of a controller area network (CAN bus). In some embodiments, a CANbus or SAE J1939 interface may be provided to other systems. FIG. 2B shows an electric motor-generator 204, which may be the electric motor-generator 130 discussed above, and which may be actuated by the AC motor controller 202. In some examples, the electric-motor generator 204 may include an electric motor-generator manufactured by Remy International, Inc. of Pendleton, Ind. FIG. 2C illustrates a water pump 206 coupled to a water pump relay 218, a water fan 208 coupled to a wafer fan relay 220, an oil pump 210 coupled to an oil pump relay 222, an oil fan 212 coupled to an oil fan relay 224, and a ground bus bar 214. Each of the water pump 206, the water fan 208, the oil pump 210, and the oil fan 212 may be coupled to a voltage supply 216 (and thus enabled) by way of their respective relay, where the relays are coupled to and actuated by a master control unit 228 (FIG. 2D). In addition, the ground bus bar 214 may be coupled to a ground plane 226 (FIG. 2D), and each of the water pump 206, the water fan 208, the oil pump 210, and the oil fan 212 may be coupled to the ground plane 226 by way of the ground bus bar 214.

In addition to the master control unit 228, FIG. 2D illustrates a DC-DC power supply 230 coupled to a DC-DC control relay 236, a brake pressure sensor 232 coupled to the master control unit 228, a ground fault detector (GFD) 234 coupled to a battery management system (BMS)/GFD relay 240, and the AC motor controller relay 238. The DC-DC power supply 230 may be coupled to the voltage supply 216 (and thus enabled) by way of the DC-DC control relay 236, which is coupled to and actuated by a master control unit 228. Similarly, the GFD 234 and a “Key On−” input of a BMS 242 (FIG. 2E) may be coupled to the voltage supply 216 by way of the BMS/GFD relay 240, which is also coupled to and actuated by the master control unit 228. The AC motor controller 202 may also be coupled to the voltage supply 216 (and thus enabled) by way of the AC motor controller relay 238, which is also coupled to and actuated by the master control unit 228. In various embodiments, the DC-DC power supply 230 and the master control unit 228 may communicate with other components of the control system circuit 200 by way of the CAN bus, as discussed below. FIG. 2E shows the “Key On−” input of a BMS 242 coupled to the BMS/GFD relay 240, as discussed above. In addition, a “Key On+” input of the BMS 242 may be coupled directly to the voltage supply 216, as shown in FIG. 2F. In some embodiments, the BMS 242 may also communicate with other components of the control system circuit 200 by way of the CAN bus, as discussed below.

Referring specifically to FIG. 2F, illustrated therein is a compressor 244 coupled to a cooling relay 248, an attitude and heading reference system (AHRS) 246 coupled to an AHRS relay 252, and an optional inverter relay 250. By way of example, the compressor may include a variable frequency drive (VFD) or variable speed drive (VSD) compressor. The compressor 244 may be coupled to the voltage supply 216 (and thus enabled) by way of the cooling relay 248, which is coupled to and actuated by a master control unit 228. Similarly, the AHRS 246 may be coupled to the voltage supply 216 (and thus enabled) by way of the AHRS relay 252, which is coupled to and actuated by a master control unit 228. In some embodiments, the AHRS 246 may communicate with other components of the control system circuit 200 by way of the CAN bus, as discussed below. In various embodiments, the control system circuit 200 further includes an inverter, as shown below in FIG. 4 , that may be coupled to the DC-DC power supply 230 and which may be optionally enabled/disabled using the inverter relay 250 by the master control unit 228. Moreover, in various embodiments, the inverter is coupled to the electric motor-generator 204 to provide power to, or receive power from, the electric motor-generator 204. It is again noted that the description of the control system circuit 200 is merely exemplary, and other aspects, advantages, and useful components will be evident to those skilled in the art, without departing from the scope of this disclosure. For example, in various embodiments, the control system circuit 200 may also include one or more of a fuse and relay module, a 12 volt battery, a fuse block, one or more battery disconnect switches, one or more electrical contactors, a pre-charge resistor, and/or other components as known in the art.

With reference now to FIG. 3 , illustrated therein is a controller area network (CAN bus) 300 used for communication of the various components of the control system circuit 200 with one another. Generally, a CAN bus is a vehicle bus standard designed to allow microcontrollers and other devices such as electronic control units (ECUs), sensors, actuators, and other electronic components, to communicate with each other in applications without a host computer. In various embodiments, CAN bus communications operate according to a message-based protocol. Additionally, CAN bus communications provide a multi-master serial bus standard for connecting the various electronic components (e.g., ECUs, sensors, actuators, etc.), where each of the electronic components may be referred to as a ‘node’. In various cases, a CAN bus node may range in complexity, for example from a simple input/output (I/O) device, sensors, actuators, up to an embedded computer with a CAN bus interface. In addition, in some embodiments, a CAN bus node may be a gateway, for example, that allows a computer to communicate over a USB or Ethernet port to the various electronic components on the CAN network. In various embodiments, CAN bus nodes are connected to each other through a two wire bus (e.g., such as a 120Ω nominal twisted pair) and may be terminated at each end by 120Ω resistors.

In particular, the CAN bus 300 is illustrated as a linear bus terminated at each end by 120Ω resistors. In some embodiments, the CAN bus 300 includes an ISO 11898-2 high speed CAN bus (e.g., up to 1 Mb/s). By way of example, the CAN bus 300 is shown as including as nodes, for example, the AC motor controller 202, the BMS 242, the AHRS 246 (sensor), the master control unit 228, the DC-DC power supply 230 (actuator), and telematics unit 302 (smart sensor). In some embodiments, the telematics unit 302 may include a global positioning system (GPS), an automatic vehicle location (AVL) system, a mobile resource management (MRM) system, a wireless communications system, a radio frequency identification (RFID) system, a cellular communications system, and/or other telematics systems. In some embodiments, the telematics unit 302 may also include the AHRS 246. In accordance with various embodiments, at least some of the sensors, actuators, and other electronic components which are not included (e.g., shown in FIG. 3 ) as CAN bus nodes, may themselves be coupled to the CAN bus 300 by way of one or more of the CAN bus nodes. For example, a voltage meter (sensor), a current meter (sensor), and one or more electrical contactors (actuators) may be coupled to the CAN bus 300 by way of the BMS 242. Similarly, the water pump 206 (actuator), the water fan 208 (actuator), the oil pump 210 (actuator), the oil fan 212 (actuator), the GFD 234 (sensor), an inverter, the brake pressure sensor 232, a trailer weight sensor, as well as other actuators, sensors, and/or electronic components may be coupled to the CAN bus 300 by way of the master control unit 228. In some examples, the electric motor-generator 204 (actuator) is coupled to the CAN bus 300 by way of the AC motor controller 202. In some embodiments, a CANbus or SAE J1939 interface may be provided to other systems, such as those of a powered vehicle to facilitate read-type access to operating parameters or otherwise observable states of systems thereof.

Referring now to FIG. 4 , illustrated therein is control system diagram 400 which provides further detail regarding connections and/or communication between and among the various control system components, some of which have been shown and described above (e.g., as part of the control system circuit 200 and/or the CAN bus 300). By way of example, the control system diagram 400 shows that the master control unit 228 is configured to operate as a ‘Master’ controller, while each of the BMS 242 and the AC motor controller 202 are configured to operate as ‘Slave’ controllers and are thereby under control of the master control unit 228. In some embodiments, and as illustrated in the control system diagram 400, the master control unit 228 provides for control (e.g., actuation of and/or receipt of a sensor output) for each of the water pump 206, the water fan 208, the oil pump 210, the oil fan 212, a trailer weight sensor 408, the DC-DC power supply 230, an inverter 412, the AHRS 246, a telematics unit 410, the GFD 234, and the brake pressure sensor 232. Additionally, the BMS 242 provides for control (e.g., actuation of and/or receipt of a sensor output) for each of a voltage meter 402, a current meter 404, and one or more electrical contactors 406. In some embodiments, the AC motor controller 202 provides for control (e.g., actuation) of the electric motor-generator 204, as discussed above.

Control Methods, Generally

Various aspects of the hybrid suspension system 100 have been described above, including aspects of the control system architecture and related components. It particular, it has been noted that the hybrid suspension system 100 is operated, by way of the control system 150 and suitable program code, in at least three modes of operation: (i) a power assist mode, (ii) a regeneration mode, and (iii) a passive mode. In at least some embodiments, the program code used to operate the control system 150 may reside on a memory storage device within the master control unit 228 (FIG. 2D). In addition, the master control unit 228 may include a microprocessor and/or microcontroller operable to execute one or more sequences of instructions contained in the memory storage device, for example, to perform the various methods described herein. In some cases, one or more of the memory storage, microprocessor, and/or microcontroller may reside elsewhere within the hybrid suspension system 100, or even at a remote location that is in communication with the hybrid suspension system 100. In some embodiments, a general purpose computer system (e.g., as described below with reference to FIG. 7 ) may be used to implement one or more aspects of the methods described herein.

A variety of control systems designs are contemplated and will be appreciated by persons of skill in the art having benefit of the present disclosure. For example, in some embodiments, control system 150 is programmed to apply an equivalent consumption minimization strategy (ECMS) or adaptive ECMS type control strategy to modulate the motive force or torque provided, at an electrically driven axle(s), as a supplement to motive force or torques that control system 150 estimates are independently applied using the fuel-fed engine and primary drivetrain of the powered vehicle. In some embodiments, control system 150 is programmed to operate in conjunction with an altitude and heading reference system (AHRS). Exemplary ECMS type and AHRS type control strategies are now described.

FIG. 5A is a flow diagram that illustrates computations of a controller that applies an equivalent consumption minimization strategy (ECMS) to the hybrid suspension system 100 design previously explained. Interactions of a programmed controller 228 with battery array 140, with a vehicle CANbus (for retrieval of operating conditions indicative of current torque delivered by fuel-fed engine through the primary drive train and current gear ratios of that primary drivetrain), and ultimately with electric motor-generator 130 via any local controller (e.g., sevcon controller 202) are all illustrated.

Based on the current SOC for battery array 140, an array of possible options for amperage discharge and charge values are calculated. These possibilities are converted to kW power as potential battery power discharge and charge possibilities. Battery inefficiencies and motor controller inefficiencies are considered along with possible electric drivetrain gear ratios to arrive at the corresponding potential electric motor torques that can be applied and resultant wheel torques which can be applied to the vehicle using electric motor-generator 130. Using the battery power discharge and charge possibilities, a corresponding diesel usage table is calculated using a lookup table that stores values for battery power equivalence based on various SOC conditions of battery array 140.

Based on current operating parameters retrieved from the vehicle CANbus (e.g., engine torque and current gear ratios in the primary drivetrain) or optionally based on estimates calculated based on a high-precision inertial measurement unit (IMU) effective torque delivered at vehicle wheels by the fuel-fed engine and the primary drivetrain is calculated or otherwise computationally estimated at controller 228. Potential supplemental torques that can be provided at wheels driven (or drivable) by electric motor-generator 130 are blended with those calculated or estimated for vehicle wheels driven by the fuel-fed engine and primary drivetrain in a calculation that back-calculates where the various additional supplemental torques would place the vehicle's engine. Then, based on these new values for the fuel-fed engine and primary drivetrain, a vehicle fuel usage consumption table is updated and, in turn, combined with (computationally summed) a charge/fuel usage table for electric motor-generator 130. Based on the current SOC, SOC targets, and SOC hysteresis, a minimum index value from the discharge fuel usage table or the charge fuel usage table is used. A motor torque at this index is retrieved from the motor torque possibilities table, and this torque demand is sent to electric motor-generator 130 via any local controller (e.g., sevcon controller 202) to be applied as supplemental torque via the electric drivetrain in a TTR hybrid configuration.

Turning to FIG. 5B, illustrated therein is a method 500 of controlling a hybrid suspension system, such as the hybrid suspension system 100 described above with reference to FIGS. 1A-1C. Generally, and in some embodiments, the method 500 provides a method for determining how much torque should be provided by the hybrid suspension system 100, and as such in which mode to operate the hybrid suspension system 100 (e.g., power assist, regeneration, or passive), in order to keep the hybrid suspension system 100, a trailer to which the hybrid suspension system 100 is coupled, and a powered vehicle towing the trailer, moving along their current trajectory at a substantially constant speed. Among other advantages, embodiments of the method 500 provide for a reduction in both fuel consumption and any associated vehicle emissions, and thus a concurrent improvement in fuel efficiency, of a powered vehicle towing the trailer, as well as improved vehicle acceleration, vehicle stability, and energy recapture (e.g., via regenerative braking).

It is also noted that while performing the method 500, aspects of the present disclosure may additionally receive data from, send data to, actuate, other otherwise interact with various components of the control system circuit 200 and the CAN bus 300, described above. Thus, one or more aspects discussed above may also apply to the method 500. Moreover, additional process steps may be implemented before, during, and after the method 500, and some process steps described above may be replaced or eliminated in accordance with various embodiments of the method 500.

Referring now to the method 500, the method 500 begins at block 502 where trailer data is received from one or more on-board sensors. As used herein, the term “on-board sensors” may be used to describe sensors that are coupled to or part of the hybrid suspension system 100, sensors that are coupled to or part of a trailer to which the hybrid suspension system 100 is attached, as well as remote sensors that may communicate (e.g., by way of cellular, wireless, RF, satellite, or other such communication) data to a receiver or transceiver that is coupled to or part of the hybrid suspension system 100 or the trailer. In some embodiments, the described sensors may be coupled to or part of the tractor 165 to which the trailer is coupled. In various embodiments, the sensors may include one or more of a brake pressure sensor (e.g., such as the brake pressure sensor 232), an altitude and heading reference system (e.g., such as the AHRS 246), one or more smart sensors (e.g., such as the telematics unit 302) which may include a global positioning system as well as other smart sensors and/or telematics systems as described above, a trailer weight sensor which may include an air bag pressure sensor (e.g., provided in a suspension assembly of the towed vehicle) or other type of weight sensor, a speed sensor, a gyroscope, an accelerometer, a magnetometer, a lateral acceleration sensor, a torque sensor, an inclinometer, and/or other suitable sensor. In various embodiments, the sensed trailer data is sent to the master control unit 228 for further processing. For example, in some embodiments, the received trailer data (e.g., the sensor output) may be filtered to smooth the sensor data and thereby mitigate anomalous sensor values. In some cases, such filtering and smoothing may be accomplished using moving averages and Kalman filters, although other smoothing and/or filtering techniques may also be used. In at least some examples, an estimated braking torque is obtained from the brake pressure sensor, an estimated weight of the trailer is obtained from the air bag pressure sensor, and a trailer acceleration and roadway incline are both obtained from the AHRS.

The method 500 then proceeds to block 504 where based at least in part on the trailer data, a total estimated torque is computed. In some embodiments, the total estimated torque includes an estimated torque to maintain movement of the hybrid suspension system 100, and a trailer to which the hybrid suspension system 100 is coupled, along their current trajectory at a substantially constant speed. In embodiments when the trailer is at least partially towed by a powered vehicle, the total estimated torque further includes an estimated torque to maintain movement of the hybrid suspension system 100, the coupled trailer, and the powered vehicle, along their current trajectory at a substantially constant speed. For purposes of this discussion, the hybrid suspension system 100, the coupled trailer, and the powered vehicle may be collectively referred to as “a hybrid trailer vehicle system (HTVS)”. Thus, in some embodiments, the tractor-trailer vehicle 160 of FIG. 1C may be referred to as an HVTS.

In an embodiment of block 504, computing the total estimated torque may include computing one or more of a plurality of forces acting on the HTVS. For example, computing the total estimated torque may include computing a driver input torque (e.g., throttle/braking of the powered vehicle), an air drag torque, a road drag torque, a road grade torque, and an acceleration torque, among others. In some embodiments, the air drag torque and the road drag torque may be dependent on a speed at which the HTVS is traveling. In some cases, the road grade torque may be dependent on an incline/decline of a roadway on which the HTVS is traveling. By way of example, the driver of the powered vehicle of the HTVS may actuate an air brake system. In such cases, embodiments of the present disclosure may utilize an air brake pressure to calculate a braking torque component of the total estimated torque. In some embodiments, the driver input torque may be substantially equal to a sum of the air drag torque, the road drag torque, the road grade torque, and the acceleration torque. In various embodiments, the total estimated torque computed at block 504 may include a currently-applied (e.g., instantaneous) HTVS torque. Based in part on the total estimated torque and an estimate and/or prediction of a driver-applied torque, as discussed in more detail below, a specified torque may be applied by way of the hybrid suspension system 100 to one or more trailer axles. Moreover, in some embodiments and based in part on the total estimated torque and an estimate and/or prediction of a driver-applied torque, a specified torque may be applied by way of the hybrid suspension system 100, as described below.

The method 500 then proceeds to block 506 where a torque applied by a powered vehicle towing the trailer is computationally estimated (e.g., by the control system 150). Stated another way, in embodiments of block 506, a torque applied by a driver of the powered vehicle (e.g., by applying throttle or braking) is estimated, for example, as a result of the hybrid suspension system 100 being autonomous from the powered vehicle and thus not having direct feedback regarding driver inputs (e.g., throttle/braking). In some embodiments, the driver-applied torque may also be predicted. Thus, in some examples, a currently-applied torque may be estimated and a subsequently applied torque may be predicted. In some embodiments, the estimated and/or predicted driver-applied torque may be based on a plurality of factors such as past driver behavior, current driver behavior, road conditions, traffic conditions, weather conditions, and/or a roadway grade (e.g., road incline or decline). As used herein, the term “driver behavior” may be used to describe a driver's operation of the powered vehicle, for example, including application of throttle, braking, steering, as well as other driver-controlled actions. Additionally, and in various embodiments, at least some of the factors used to estimate and/or predict the driver-applied torque may include data received from one or more of the on-board sensors, described above, including GPS or inclinometer data that may be used to determine a present roadway grade and/or predict an upcoming roadway grade. For example, if the upcoming roadway grade includes a positive grade (e.g., an incline), the driver may in some embodiments be expected to apply additional throttle. In some cases, if the upcoming roadway grade includes a negative grade (e.g., a decline), the driver may in some embodiments be expected to apply the brakes (e.g., of the powered vehicle). In some embodiments, if the upcoming roadway grade is substantially flat, the driver may in some embodiments be expected to neither apply additional throttle nor apply the brakes. In some examples, at least some of the factors used to estimate and/or predict the applied torque may further include traffic data, weather data, road data, or other similar data. Similarly, if the upcoming roadway includes heavy traffic, poor road conditions (e.g., pot holes, unpaved sections, etc.), or if weather has caused hazardous driving conditions (e.g., rain, flooding, strong crosswinds, etc.), the driver may in some embodiments be expected to apply the brakes. Thus, in accordance with some embodiments, knowledge of an upcoming roadway grade, combined with a plurality of other data (e.g., traffic, weather, road data) and the driver's current and/or past behavior may be used to estimate and/or predict the driver-applied torque. It will be understood that the driver behaviors discussed above, with respect to roadway grade and road/weather conditions, are merely exemplary. Various other behaviors (e.g., apply throttle during a negative grade or apply brakes during a positive grade) are possible as well, without departing from the scope of the present disclosure.

The method 500 then proceeds to block 508 where based at least in part on the estimated and/or predicted torque (block 506) and the total estimated torque (block 504), a specified trailer torque is computed and applied to one or more of the trailer axles. In particular, the specified trailer torque is applied to the one or more of the trailer axles by way of the hybrid suspension system 100, as described herein. Additionally, in an embodiment of block 508, the hybrid suspension system 100 is operated in the appropriate one of the at least three modes of operation (e.g., power assist, regeneration, or passive) in order to provide the specified trailer torque. In some embodiments, the specified trailer torque is computed, at least in part, by utilizing the estimated and/or predicted driver-applied torque in an energy optimization algorithm that utilizes an equivalent consumption minimization strategy (ECMS) to simultaneously optimize the fuel consumption of the powered vehicle and the energy usage (e.g., battery charge) of the hybrid suspension system 100.

An aspect of the energy optimization algorithm is illustrated in more detail in FIG. 5C, which provides a method 550. In some embodiments, the method 550 may be performed as part of, or in addition to, the method 500. For example, in some cases, the method 550 may be performed as part of block 508 of the method 500, where the specified torque is computed and applied to the one or more trailer axles. By way of example, the method 550 begins at block 552 where a first plurality of torques that may be applied by the powered vehicle, and a second plurality of torques that may be applied at the trailer (e.g., applied by the electric motor-generator), are determined. In some embodiments, the first plurality of torques may include a range of torque values which the powered towing vehicle is capable of providing (e.g., by way of a fuel-consuming engine, an electric motor, or other means of providing a motive force). Similarly, and in some embodiments, the second plurality of torques may include a range of torque values which the hybrid suspension system 100 is capable of providing (e.g., by way of the energy storage system and the electric motor-generator coupled to one or more drive axles).

The method 550 then proceeds to block 554, where the first plurality of torques is mapped onto a fuel usage map. For example, in some embodiments, a difference between the total estimated torque (block 504) and the second plurality of torques (e.g., each torque of a range of possible torque values which the hybrid suspension system 100 can provide) is determined, where the difference provides a set of corresponding torque values that would be provided by the powered vehicle (e.g., by the fuel-fed engine of the powered vehicle). In various embodiments, the set of corresponding torque values may be used to generate a torque-to-fuel usage map for the powered vehicle. At block 556 of the method 550, the second plurality of torques may be used to similarly generate a torque-to-energy usage map for the hybrid suspension system 100.

Thereafter, at block 558 of the method 550, an optimal combination of a first torque from the first plurality of torques, and a second torque from the second plurality of torques, is selected. By way of example, and in an embodiment of block 558, the torque-to-energy usage map may be converted to another torque-to-fuel usage map, so that mappings of the powered vehicle and the hybrid suspension system 100 may be more readily compared. In some cases, the torque-to-fuel usage map corresponding to the hybrid suspension system 100 is subtracted from the torque-to-fuel usage map corresponding to the powered vehicle (e.g., the fuel-fed engine of the powered vehicle), thereby resulting in a combined powered vehicle/hybrid suspension system usage map. Thereafter, in some embodiments, an optimal (e.g., minimum) fuel usage from the combined usage map is determined, including a corresponding index value. In some cases, the corresponding index value is then used to select an optimal torque value for the hybrid suspension system 100 from the torque-to-energy usage map, and the optimal torque value for the hybrid suspension system 100 is applied, in an embodiment of both blocks 508 and 558. In a more general sense, embodiments of the present disclosure may be used to estimate a current torque demand of the HTVS. Using the estimated torque demand, at least some embodiments may be used to determine an amount of fuel efficiency gain (e.g., of the powered vehicle) and/or energy efficiency gain (e.g., of the hybrid suspension system 100) that may be achieved by operating the hybrid suspension system 100 in a particular mode, while applying a particular torque, thereby providing for selection of the optimal torque value for the hybrid suspension system 100.

With reference now to FIG. 6 , illustrated therein is an exemplary functional block diagram 600 for controlling the hybrid suspension system 100, described above. In particular, the block diagram 600 illustrates exemplary relationship, in at least some embodiments, among various components of an HVTS, such as the tractor-trailer vehicle 160 of FIG. 1C. Moreover, at least some aspects of the methods 500, 550, discussed above, may be better understood with reference to FIG. 6 . For example, FIG. 6 illustrates the autonomous nature of the hybrid suspension system 100, where the hybrid suspension system 100 is able to operate without direct commands or signals from the powered towing vehicle (e.g., such as the tractor 165), to independently gain information about itself, the trailer 170, and the environment (e.g., by way of the trailer sensing system), and to make decisions and/or perform various functions based on one or more algorithms stored in the control system 150.

The autonomous nature of the hybrid suspension system 100 is further exemplified, in at least some embodiments, by the functional block diagram 600 including two separate control loops, a hybrid suspension system control loop 610 and a powered towing vehicle control loop 620. In the powered vehicle control loop 620, a driver 622 may apply a throttle 624 or a brake 626, which is then applied to the powered vehicle (e.g., such as the tractor 165). In various embodiments, a response of the powered vehicle to the applied throttle 624/brake 626 (e.g., acceleration/deceleration of the powered vehicle) may be provided as feedback to the driver 622, which the driver 622 may then further respond to by applying additional throttle 624 or brake 626, or neither throttle 624/brake 626. In some examples, the powered vehicle may also provide feedback (e.g., to the driver 622) via throttle 624/brake 626 inputs.

Independent from the powered vehicle control loop 620, the hybrid suspension control loop 610 may operate in a substantially similar manner to the methods 500, 550 described above. For example, in at least some embodiments, the hybrid suspension control system 150 may receive trailer data from a trailer sensor system 602, which may include any of the one or more sensors discussed above. In some cases, the trailer sensor system 602 may include the on-board sensors discussed above. In some embodiments, the control system 150 may compute a total estimated torque and computationally estimate a torque applied by the powered vehicle 165 (e.g., which may include estimating throttle and/or braking). In some embodiments, based on the total estimated torque and the computationally estimated torque of the powered vehicle, a specified trailer torque may be computed and applied to the one or more trailer axles 120, by way of the electric motor-generator 130. In various examples, the driven one or more trailer axles 120 may provide feedback to the control system 150, for further computation and application of torque. In some cases, the one or more driven trailer axles 120 may also provide feedback to the electric motor-generator 130. In at least some embodiments, the hybrid suspension system 100 may sense one or more pneumatic brake lines from the powered vehicle.

Control Methods, Examples and Further Discussion

The hybrid suspension system 100 may be used, for example together with aspects of the control methods described above, to operate in a variety of different modes (e.g., power assist, regeneration, and passive modes) and thus perform a variety of different functions. In various examples, the hybrid suspension system 100 may be used to provide a power boost (e.g., to the HVTS) during acceleration and/or when going up an incline by operating in the power assist mode, thereby depleting energy from the energy storage system. In addition, the hybrid suspension system 100 may replenish that energy by operating in the regeneration mode (e.g., using regenerative braking) when decelerating and/or when going down a decline. As discussed above, operation in one of the various modes may be determined according to a variety of inputs and/or data (e.g., from sensors, calculated values, etc.) such as discussed above. In various examples, the hybrid suspension system 100 and associated methods may provide, among other benefits, optimal application of power (e.g., as discussed in the example below), increased fuel mileage, decreased fuel emissions, and superior load stabilization. Of particular note, embodiments of the hybrid suspension system 100 described herein are configured to operate generally independently of the powered vehicle to which the trailer may be attached. Thus, any type of powered vehicle may hook up and tow a trailer, including the hybrid suspension system 100 attached thereunder, and the hybrid suspension system 100 will automatically adapt to the powered vehicle's behavior.

With respect to optimal application of power as discussed above, there are scenarios in which battery power could be used most effectively at a given time, for example, knowing that battery power may be (i) regenerated in the near future (e.g., based on an upcoming downhill roadway grade) or (ii) needed in the near future (e.g., based on an upcoming uphill roadway grade). Such information (e.g., regarding the upcoming roadway) may be gathered from GPS data, inclinometer data, and/or other sensor data as described above. In some embodiments, the hybrid suspension system 100 may alternatively and/or additionally periodically query a network server, or other remote sever/database, to provide an upcoming roadway grade.

For purposes of illustration, consider an example where an HTVS is traveling along substantially flat terrain, while the battery array 140 of the hybrid suspension system 100 is at about a 70% state of charge (SOC). Consider also that there is an extended downhill portion of roadway coming up that would provide for regeneration about 40% SOC of the battery array 140 (e.g., while operating the hybrid suspension system 100 in the regeneration mode). Absent knowledge of the upcoming extended downhill portion of the roadway, some embodiments may operate in the passive mode on the substantially flat terrain, while beginning to regenerate the battery array 140 once the HTVS reaches the extended downhill portion of roadway. In such cases, about 30% SOC may be regenerated before the battery array 140 is fully charged. Thus, the system may not be able to regenerate further, and about 10% SOC that could have been captured may be lost.

In some embodiments, the predictive road ability discussed herein provides knowledge of the upcoming extended downhill portion of roadway. As such, the hybrid suspension system 100 may autonomously engage the power assist mode while traveling along the substantially flat terrain, such that about 10% SOC of the battery array 140 is used prior to reaching the extended downhill portion of roadway, thereby improving fuel efficiency of the HTVS (e.g., while on the substantially flat terrain), while still regenerating about 30% SOC while traveling along the extended downhill portion. Such system operation, including the predictive road ability, advantageously provides for both improved fuel efficiency of the HTVS efficient use of the battery array 140 (e.g., as it may be undesirable to have the battery array nearly full or nearly empty when there is an opportunity to regenerate or provide power assistance).

In another example, consider a case where the battery array 140 is at about 10% SOC and the HTVS is traveling along substantially flat terrain. Consider also that an extended uphill portion of roadway is coming up that would optimally be able to use about 20% SOC of the battery array 140 (e.g., while operating the hybrid suspension system 100 in the power assist mode). Once again, absent knowledge of the upcoming extended uphill portion of the roadway, some embodiments may operate in the passive mode on the substantially flat terrain, while beginning to use energy (e.g., operating in the power assist mode) once the HTVS reaches the extended uphill portion of the roadway. Thus, in such an example, the battery array 140 may expend its 10% SOC before the hybrid suspension system 100 may not be able to assist further. Stated another way, about 10% SOC that could have been effectively used by the HTVS while traveling along the extended uphill portion of the roadway is not available.

As discussed above, the predictive road ability provides knowledge of the upcoming extended downhill portion of roadway. As such, the hybrid suspension system 100 may autonomously engage the regeneration mode while traveling along the substantially flat terrain, such that about 10% SOC of battery array 140 is regenerated, for a total of about 20% SOC, prior to reaching the extended uphill portion of the roadway. While this may result in a temporary decrease in fuel efficiency, the efficiency gains afforded by operating the hybrid suspension system 100 in the power assist mode for the duration of the extended uphill portion of the roadway (e.g., and optimally using the 20% SOC of the battery array 140) outweigh any potential efficiency reductions that may occur by regenerating on the substantially flat terrain.

In addition to using the various sensors, data, networking capabilities, etc. to determine whether the HTVS is traveling along substantially flat terrain, uphill, or downhill, embodiments of the present disclosure may be used to determine whether the HTVS is hitting a bump or pothole, turning a corner, and/or accelerating. By accounting for dynamics of the trailer and measuring angles and accelerations (e.g., in 3-dimensional space), embodiments of the present disclosure may provide for measurement of: (i) acceleration, deceleration, and angle of inclination of the trailer (e.g., by taking readings lengthwise), (ii) side-to-side (e.g., turning force) motion and banking of a roadway (e.g., by taking readings widthwise), (iii) smoothness of the roadway, pot holes, and/or wheels riding on a shoulder (side) of the road (e.g., by taking readings vertically). Utilizing such information, embodiments of the present disclosure may be used to brake wheels individually, for example, while still supplying power (e.g., by the power assist mode) to other wheels, thereby increasing trailer stability. In addition, and in some embodiments, by monitoring the acceleration, axle speed and incline of the roadway over time and by applying an incremental amount of torque and measuring the response in real time, the controller may back-calculate a mass of the trailer load. In some embodiments, a weight sensor may also be used, as described above. In either case, such information may be used by the system for application of a proper amount of torque to assist in acceleration of the HTVS without over-pushing the powered vehicle.

In some examples, the system may further be used to monitor one or more pneumatic brake lines, such that embodiments of the present disclosure provide a ‘fail safe’ mode where the hybrid suspension system 100 will not accelerate (e.g., operate in a power assist mode) while a driver (e.g. of the powered vehicle) is actuating a brake system. In various embodiments, by monitoring feedback pressure of each wheel's brake lines, as well as their respective wheel speeds, the present system can determine how each brake for a particular wheel is performing. Thus, in various examples, embodiments of the present disclosure may provide for braking and/or powering of different wheels independently from one another for increased trailer stability. In some cases, this may be referred to as “torque vectoring”. By way of example, such torque vectoring embodiments may be particularly useful when there are differences in roadway surfaces upon which each of a plurality of wheels of the HTVS is traveling (e.g., when roadway conditions are inconsistent, slippery, rough, etc.).

Embodiments disclosed herein may further be employed to recapture energy via regenerative braking, as described above. In some examples, the application of the brakes, and/or various combinations of deceleration, axle speed, trailer weight and incline/decline readings may dictate, at least in part, an ability and amount of regeneration possible by the hybrid suspension system 100. In various embodiments, regenerative braking may persist until the energy storage system is fully charged, until a predetermined minimum level of stored energy has been achieved, or until the powered trailer axle has reached a minimum threshold rotational speed. Additionally, for example in some extreme conditions, different amounts of braking may be applied to each wheel in order to reduce a potential of jack-knifing or other dangerous conditions during operation of the HTVS. As a whole, regenerative braking may be used to lighten a load on a mechanical braking system (e.g., on the powered vehicle and/or on the trailer), thereby virtually eliminating a need for a loud compression release engine brake system (e.g., Jake brake system). In some cases, by applying both regenerative braking and friction braking, the HTVS may be able to brake much faster and have shorter stopping distances. In addition, and in various embodiments, the present system may be deployed with two pneumatic brake lines (e.g., which may including existing brake lines), while an entirety of the controls (e.g., including sensor input processing, mode of operation control, aspects of the various methods described above, and other decision-making controls) may reside entirely within the hybrid suspension system 100 itself (e.g., and in many respects, within the control system 150).

Energy Capture and Management, Further Discussion

With respect to energy recapture, the above discussion is primarily directed to charging the energy storage system (e.g., the battery array) by regenerative braking; however, other methods of energy recapture are possible and within the scope of this disclosure. For example, in some embodiments, a hydraulic system (e.g., used to capture energy via air pressure or fluid pressure), flywheels, solar panels, or a combination thereof may be used for energy recapture. Additionally, in some cases, the HVTS 160 may include shocks (e.g., as part of a suspension of the powered vehicle and/or of the hybrid suspension system 100), which may include regenerative shock absorbers, that may be used to capture electrical energy via the motion and/or vibration of the shocks. In some embodiments, energy captured by one or more of the above methods may be used to charge the energy storage system.

Further, embodiments disclosed herein may use the recaptured energy not only to apply the motive rotational force using the electric motor-generator, but also to provide power that may be used for powering a host of devices and/or systems, both on the trailer and on the powered vehicle. For example, the recaptured energy may be used to power a lift gate, a refrigeration unit, a heating ventilation and air conditioning (HVAC) system, pumps, lighting, appliances, entertainment devices, communications systems, other 12V-powered devices, and/or to provide an auxiliary power unit (APU), among others. Regardless of where the power is being provided, embodiments disclosed herein provide for energy storage and management to be on-trailer (e.g., via the battery array 140, the master control unit 228, and the BMS 242).

When configured to provide an APU, the HVTS 160 may include an APU interface to provide power from the energy storage system (e.g., the battery array) to the powered vehicle to power one or more devices and/or systems on the powered vehicle. In some embodiments, the APU interface may include an SAE J2891 interface. In various examples, the APU interface may physically couple to an electrical interface on the powered vehicle so that power from the energy storage system may be transferred to the powered vehicle. In some embodiments, an inverter, such as the inverter described above, may be coupled between the energy storage system and the APU interface to supply AC power to the powered vehicle. In some cases, a step-down DC-DC power supply may be coupled between the energy storage system and the APU interface to supply DC power to the powered vehicle. In some embodiments, an electrical cable may be used to transfer electrical power from the energy storage system on the towed vehicle to the powered vehicle and for bi-directionally conveying data between the powered vehicle and at least a battery management system of the towed vehicle.

In at least some embodiments, a control interface is provided in the powered towing vehicle. By way of example, the control interface may be coupled to the battery management system of the towed vehicle. In various embodiments, the control interface may provide an in-towing-vehicle (e.g., within a cab of the powered vehicle) display of state of charge for the energy storage system on the towed vehicle, a switch or control of a switch to enable and disable supply of electrical power to the powered towing vehicle, and/or mode control for selectively controlling an operating mode of the battery management system. In some embodiments, and in at least one selectable mode of the battery management system, energy recovered using the drive axle in a regenerative braking mode (or energy recovered using one of the other methods described above) is used to bring the energy storage system to a substantially full state of charge. Further, in some embodiments, and in at least another selectable mode of the battery management system, state of charge of the energy storage system is managed to a dynamically varying level based at least in part on uphill and downhill grades along a current or predicted route of travel of the HVTS 160. In at least some embodiments, the control interface may be integrated with the HVAC system on the powered towing vehicle, the HVAC system powered from the energy storage system on the towed vehicle at least during some extended periods of time during which an engine of the towing vehicle is off (e.g., when the HVTS 160 is stopped at a rest area, weigh station, pick-up location, drop-off location, or other location).

Computer System for Implementing the Various Methods

Referring now to FIG. 7 , an embodiment of a computer system 700 suitable for implementing various aspects of the control system 150 and methods 500, 550, is illustrated. It should be appreciated that any of a variety of systems which are used for carrying out the methods described herein, as discussed above, may be implemented as the computer system 700 in a manner as follows.

In accordance with various embodiments of the present disclosure, computer system 700, such as a computer and/or a network server, includes a bus 702 or other communication mechanism for communicating information, which interconnects subsystems and components, such as a processing component 704 (e.g., processor, micro-controller, digital signal processor (DSP), etc.), a system memory component 706 (e.g., RAM), a static storage component 708 (e.g., ROM), a disk drive component 710 (e.g., magnetic or optical), a network interface component 712 (e.g., modem or Ethernet card), a display component 714 (e.g., CRT or LCD), an input component 718 (e.g., keyboard, keypad, or virtual keyboard), a cursor control component 720 (e.g., mouse, pointer, or trackball), a location determination component 722 (e.g., a Global Positioning System (GPS) device as illustrated, a cell tower triangulation device, and/or a variety of other location determination devices known in the art), and/or a camera component 723. In one implementation, the disk drive component 710 may comprise a database having one or more disk drive components.

In accordance with embodiments of the present disclosure, the computer system 700 performs specific operations by the processor 704 executing one or more sequences of instructions contained in the memory component 706, such as described herein with respect to the control system 150 and methods 500, 550. Such instructions may be read into the system memory component 706 from another computer readable medium, such as the static storage component 708 or the disk drive component 710. In other embodiments, hard-wired circuitry may be used in place of or in combination with software instructions to implement the present disclosure.

Logic may be encoded in a computer readable medium, which may refer to any medium that participates in providing instructions to the processor 704 for execution. Such a medium may take many forms, including but not limited to, non-volatile media, volatile media, and transmission media. In one embodiment, the computer readable medium is non-transitory. In various implementations, non-volatile media includes optical or magnetic disks, such as the disk drive component 710, volatile media includes dynamic memory, such as the system memory component 706, and transmission media includes coaxial cables, copper wire, and fiber optics, including wires that comprise the bus 702. In one example, transmission media may take the form of acoustic or light waves, such as those generated during radio wave and infrared data communications.

Some common forms of computer readable media includes, for example, floppy disk, flexible disk, hard disk, magnetic tape, any other magnetic medium, CD-ROM, any other optical medium, punch cards, paper tape, any other physical medium with patterns of holes, RAM, PROM, EPROM, FLASH-EPROM, any other memory chip or cartridge, carrier wave, or any other medium from which a computer is adapted to read. In one embodiment, the computer readable media is non-transitory.

In various embodiments of the present disclosure, execution of instruction sequences to practice the present disclosure may be performed by the computer system 700. In various other embodiments of the present disclosure, a plurality of the computer systems 700 coupled by a communication link 724 to a network (e.g., such as a LAN, WLAN, PTSN, and/or various other wired or wireless networks, including telecommunications, mobile, and cellular phone networks) may perform instruction sequences to practice the present disclosure in coordination with one another.

The computer system 700 may transmit and receive messages, data, information and instructions, including one or more programs (i.e., application code) through the communication link 724 and the network interface component 712. The network interface component 712 may include an antenna, either separate or integrated, to enable transmission and reception via the communication link 724. Received program code may be executed by processor 704 as received and/or stored in disk drive component 710 or some other non-volatile storage component for execution.

Where applicable, various embodiments provided by the present disclosure may be implemented using hardware, software, or combinations of hardware and software. Also, where applicable, the various hardware components and/or software components set forth herein may be combined into composite components comprising software, hardware, and/or both without departing from the scope of the present disclosure. Where applicable, the various hardware components and/or software components set forth herein may be separated into sub-components comprising software, hardware, or both without departing from the scope of the present disclosure. In addition, where applicable, it is contemplated that software components may be implemented as hardware components and vice-versa.

Software, in accordance with the present disclosure, such as program code and/or data, may be stored on one or more computer readable mediums. It is also contemplated that software identified herein may be implemented using one or more general purpose or specific purpose computers and/or computer systems, networked and/or otherwise. Where applicable, the ordering of various steps described herein may be changed, combined into composite steps, and/or separated into sub-steps to provide features described herein. 

What is claimed is:
 1. An apparatus comprising: a towed vehicle for use in combination with a towing vehicle, the towed vehicle having an electrically powered drive axle; and a computer system comprising a processing component and a system memory component containing one or more sequences of instructions which, when executed using the processing component, cause the computer system, based in part on trailer data associated with a plurality of characteristics of the towed vehicle, to: assess kinematic variables and computationally-estimated operational states based on operating parameters of the towing vehicle, estimate a total amount of torque required to maintain movement of the towed vehicle and the towing vehicle at a constant velocity, estimate an amount of torque applied by the towing vehicle, and estimate a specific amount of torque to be generated by the electrically powered drive axle based on the estimated total amount of torque and the estimated amount of torque applied by the towing vehicle, where the electrically powered drive axle is to provide the specific amount of torque to the towing vehicle.
 2. The apparatus of claim 1, comprising an auxiliary power unit (APU) interface to supply electrical power from an energy store to the towing vehicle.
 3. The apparatus of claim 1, wherein the electrically powered drive axle is configured to supply supplemental torque to one or more wheels of the towed vehicle, the supplemental torque being a supplement to the torque applied by the towing vehicle.
 4. The apparatus of claim 1, wherein the electrically powered drive axle is configured to supplement primary motive forces applied through a fuel-fed engine and a separate drivetrain of the towing vehicle.
 5. The apparatus of claim 4, wherein the primary motive forces are supplemented while the towed vehicle travels over a roadway and in any of a power assist mode, a regeneration mode, and a passive mode.
 6. The apparatus of claim 1, comprising an energy store on the towed vehicle, the energy store configured to supply the electrically powered drive axle with electrical power.
 7. The apparatus of claim 1, comprising an energy store on the towed vehicle, the energy store configured to receive energy recovered using the drive axle in a regenerative braking mode of operation.
 8. The apparatus of claim 1, wherein the operating parameters are measured using a CAN bus interface or an SAE J1939 201308 interface, interface, wherein the operating parameters include trailer data received from one or more on-board sensors, and wherein the computationally-estimated operational states include states of a fuel-fed engine and of a drive train.
 9. The apparatus of claim 3, wherein the supplemental torque is modulated by an electric drive controller using an equivalent consumption minimization strategy (ECMS) or adaptive ECMS control strategy and the data associated with the plurality of characteristics. 